You can find on a thread is called a mastering app and it in an Caustic 3.2 testing section. The third page of the thread contains one of the Rey's comments. Link is posted there.
Listen to Rej by MELEVEN #np on #SoundCloud
In case anyone else finds themselves in this thread looking for this mysterious unicorn of an app your search ends here.
The Mastering App beta no longer starts up. Just shows a "Beta period expired" message.
I was hoping I could just use my Android tablet for a complete production (for funsies) but looks like I'm heading to my PC.
LOVE Caustic. Hope it lives on. Cheers.
I feel your frustration man. I've been usin "wave editor" app for masterin my Caustic mixes. I love Caustic but I'm startin to feel the limitations. Good luck.
Actually the app will run if you set the time of your device to something before the end of 2016 or something like that, I can't remember exactly. It's not an ideal solution but better than nothing.